Abstract
The unfolded protein response (UPR) is one of the major cell-autonomous proteostatic stress responses. The UPR has been implicated in the pathogenesis of neurodegenerative diseases and is therefore actively investigated as therapeutic target. In this respect, cell non-autonomous effects of the UPR including the reported cell-to-cell transmission of UPR activity may be highly important. A pharmaca-based UPR induction was employed to generate conditioned media (CM) from CM-donating neuronal ('donor') cells (SK-N-SH and primary mouse neurons). As previously reported, upon subsequent transfer of CM to naive neuronal 'acceptor' cells, we confirmed UPR target mRNA and protein expression by qPCR and automated microscopy. However, UPR target gene expression was also induced in the absence of donor cells, indicating carry-over of pharmaca. Genetic induction of single pathways of the UPR in donor cells did not result in UPR transmission to acceptor cells. Moreover, no transmission was detected upon full UPR activation by nutrient deprivation or inducible expression of the heavy chain of immunoglobulin M in donor HeLa cells. In addition, in direct co-culture of donor cells expressing the immunoglobulin M heavy chain and fluorescent UPR reporter acceptor HeLa cells, UPR transmission was not observed. In conclusion, carry-over of pharmaca is a major confounding factor in pharmaca-based UPR transmission protocols that are therefore unsuitable to study cell-to-cell UPR transmission. In addition, the absence of UPR transmission in non-pharmaca-based models of UPR activation indicates that cell-to-cell UPR transmission does not occur in cell culture.
| Original language | English |
|---|---|
| Pages (from-to) | 208-220 |
| Number of pages | 13 |
| Journal | Journal of Neurochemistry |
| Volume | 152 |
| Issue number | 2 |
| DOIs | |
| Publication status | Published - Jan 2020 |
Bibliographical note
© 2019 The Authors. Journal of Neurochemistry published by John Wiley & Sons Ltd on behalf of International Society for Neurochemistry.Funding
We thank Ingrid Saarloos and Robbert Zalm for cloning and producing viral particles, Desiree Schut for primary neuron culture, Jurjen Broeke for expert help with confocal microscopy and Rob Zwart and Fabian Bangel for general laboratory support. We thank David Ron for providing the Fv2E‐PERK‐expressing CHO cell line and for scientific discussion and Jeroen Hoozemans for the THP‐1 cells. We thank Matthijs Verhage for scientific discussion and the Molecular Neurodegeneration group (Functional Genomics, VU university, Amsterdam) for critical reading of the manuscript and discussion. This study was supported by grants from Deltaplan Dementie (ZonMW Memorabel/Alzheimer Nederland 733050101) and Weston Brain Institute (NR160014) to WS. The authors declare no conflict of interest. All experiments were conducted in compliance with the ARRIVE guidelines. We thank Ingrid Saarloos and Robbert Zalm for cloning and producing viral particles, Desiree Schut for primary neuron culture, Jurjen Broeke for expert help with confocal microscopy and Rob Zwart and Fabian Bangel for general laboratory support. We thank David Ron for providing the Fv2E-PERK-expressing CHO cell line and for scientific discussion and Jeroen Hoozemans for the THP-1 cells. We thank Matthijs Verhage for scientific discussion and the Molecular Neurodegeneration group (Functional Genomics, VU university, Amsterdam) for critical reading of the manuscript and discussion. This study was supported by grants from Deltaplan Dementie (ZonMW Memorabel/Alzheimer Nederland 733050101) and Weston Brain Institute (NR160014) to WS. The authors declare no conflict of interest. All experiments were conducted in compliance with the ARRIVE guidelines.
| Funders | Funder number |
|---|---|
| Deltaplan Dementie | |
| ZonMW Memorabel/Alzheimer Nederland | 733050101 |
| Weston Brain Institute | NR160014 |
| ZonMw |
